Why is this hook causing ICS to have a parse error in ACP?

[MrFisc]

All of the following testing was done on a production style ICS installation without `IN_DEV=true` or the developer toolset installed. It was just a naked ICS 4.5 installation with only my application installed as a third party application.

The hook in question:

//<?php

/* To prevent PHP errors (extending class does not exist) revealing path */
if ( !defined( '\IPS\SUITE_UNIQUE_KEY' ) )
{
	exit;
}

class ts3integration_hook_AppLogo extends _HOOK_CLASS_
{

/* !Hook Data - DO NOT REMOVE */
public static function hookData() {
 return array_merge_recursive( array (
  'appmenu' => 
  array (
    0 => 
    array (
      'selector' => '#acpAppList',
      'type' => 'add_before',
      'content' => '',
    ),
  ),
), parent::hookData() );
}
/* End Hook Data */


}

Note that it has no content in it.

The parser error I see is:

Quote

syntax error, unexpected 'endforeach' (T_ENDFOREACH), expecting elseif (T_ELSEIF) or else (T_ELSE) or endif (T_ENDIF)

How I verified it was my hook

When i include this hook in my project, compile my project and install it on a fresh installation of IPS, I get a 500 error. 

After a lot of debugging i've confirmed it is this hook that's causing the issue by filtering it out in the \IPS\Theme PHP file (./system/Theme/Theme.php).

if ($data['class'] != 'ts3integration_hook_AppLogo') {
    $class = "IPS\\Theme\\" . $data['class'] . "_tmp";
    $templateHooks = array_merge_recursive( $templateHooks, $class::hookData() );
}

When I wrap that code in an if statement filtering out my hook, the page loads just fine.

How I debugged further

I found the relevant code in Theme.php and updated it to print a lot of information.

try
{
	if ( @eval( $compiledGroup ) === FALSE )
	{
		throw new \IPS\Theme\TemplateException( 'Invalid Template', 1000, NULL, array( 'group' => $group, 'app' => $app, 'location' => $location ), $this );
	}
}
catch ( \ParseError $e )
{
    header('Content-Type: text/plain;');
    echo $app . '/' . $location . '/' . $group . PHP_EOL;
    print_r($e);
    echo $compiledGroup;
    exit;
}

Which resulted in this

core/admin/global
ParseError Object
(
    [message:protected] => syntax error, unexpected 'endforeach' (T_ENDFOREACH), expecting elseif (T_ELSEIF) or else (T_ELSE) or endif (T_ENDIF)
    [string:Error:private] => 
    [code:protected] => 0
    [file:protected] => /var/www/html/system/Theme/Theme.php(854) : eval()'d code
    [line:protected] => 238
    [trace:Error:private] => Array
        (
            [0] => Array
                (
                    [file] => /var/www/html/system/Dispatcher/Admin.php
                    [line] => 120
                    [function] => getTemplate
                    [class] => IPS\_Theme
                    [type] => ->
                )

            [1] => Array
                (
                    [file] => /var/www/html/system/Dispatcher/Dispatcher.php
                    [line] => 109
                    [function] => init
                    [class] => IPS\Dispatcher\_Admin
                    [type] => ->
                )

            [2] => Array
                (
                    [file] => /var/www/html/admin/index.php
                    [line] => 14
                    [function] => i
                    [class] => IPS\_Dispatcher
                    [type] => ::
                )

        )

    [previous:Error:private] => 
)

// REMOVED LONG $compiledGroup OUTPUT

The $compiledGroup output was too long to display here, however I did discover which line was causing the issue by running it through a PHP syntax validator and found the unexpected `endforeach;`. You can see it on the last line of this block:
 

if ( $appAndModule . "_" . $key === $currentItem ):
$return .= <<<CONTENT
>
</ul>
</li>
								
CONTENT;

endforeach;

Conclusion

I don't understand how my hook above causes this issue. Especially since the unexpected endforeach; has nothing to do with my hook. To me this seems like a bug in ICS and not an issue with my application, but I can't tell for certain.

Edited August 30, 2020 by MrFisc

[bfarber]

Please send me a PM with the hook in question. This specific error has actually come up a few times in 4.5 from different apps and I have been writing it off as the hook being incompatible, but I'd like to do some further testing to see if something else might be up.

[Ryan Ashbrook]

A fix for this should be forthcoming in 4.5.2.